Up to now, it has been a general practice to raise and lower sceneries by means of cables passed through pulleys secured to roof joists on the stage. The cables are generally passed through further pulleys down to a control station where an operator is located. In a complex play, it is common to have up to fifty battens which have to be operated at some time during the play. This often requires the attendance of several operators, which increases the cost of labor and also takes considerable space along one wall of the stage. Moreover, due to the several counterweights and because the pulleys exert horizontal stresses on the roof joists, the same often require strengthening.